Thousands of students across the US are expected to put their pencils down and walk out of school to demonstrate against gun violence.

Organisers say nearly 3 000 walkouts are planned in the biggest demonstration yet of the student activism that has emerged following the massacre of 17 people at Marjory Stoneman Douglas High School.

Read: No safe haven as shootings rock US schools

The protests have drawn mixed reactions from school administrators. While some applaud students for taking a stand, others threatened discipline.

Some students say they don't care about the consequences, the issue is too important to remain silent.

Kara Litwin is a senior at Pope High School in suburban Atlanta. She says change never happens without backlash.